Deflation compression algorithm for huge data streams - c++

Question

I've got C++ program that is getting data buffer from time to time, and should add it to existing compressed file.
I tried to make POC by reading 1k chunks from some file, passing them to compressed stream and uncompress it when the data is over.
I use Poco::DeflatingOutputStream to compress each chunk to the file, and Poco::InflatingOutputStream to check that after decompressing I get the original file.
However, it seems that after decompressing the stream my data went almost identical to the original file, except that between every 2 consecutive chunks of data i get a few garbage characters such as : à¿_ÿ
here's an example of line that is split between 2 chunks. the original line looks like that :
elevated=0 path=/System/Library/CoreServices/Dock.app/Contents/MacOS/Dock exist
while the decompressed line is :
elevated=0 path=/System/Libr à¿_ÿary/CoreServices/Dock.app/Contents/MacOS/Dock exist
May 19 19:12:51 PANMMUZNG8WNREM kernel[0]: pid=904 uid=1873876126 sbit=0
any idea what am i doing wrong. Here's my POC code:
int zip_unzip() {
std::ostringstream stream1;
Poco::DeflatingOutputStream gzipper(stream1, Poco::DeflatingStreamBuf::STREAM_ZLIB);
std::ifstream bigFile("/tmp/in.log");
constexpr size_t bufferSize = 1024;
char buffer[bufferSize];
while (bigFile) {
bigFile.read(buffer, bufferSize);
gzipper << buffer;
}
gzipper.close();
std::string zipped_string = stream1.str();
//////////////////
std::ofstream stream2("/tmp/out.log", std::ios::binary);
Poco::InflatingOutputStream gunzipper(stream2, InflatingStreamBuf::STREAM_ZLIB);
gunzipper << zipped_string;
gunzipper.close();
return 0;
}

Answer 1

Ok, i just realized i used the '<<' operator on each read from the HugeFile (the original decompressed file) without care, since there was no null termination symbol '/0' at the end of each window i read from the file.
That's the fixed version :
#include <stdio.h>
#include <fstream>
#include <Poco/DeflatingStream.h>
#include <Poco/Exception.h>
#include <iostream>
int BetterZip()
{
try {
// Create gzip file.
std::ofstream output_file("/tmp/out.gz", std::ios::binary);
Poco::DeflatingOutputStream output_stream(output_file, Poco::DeflatingStreamBuf::STREAM_GZIP);
// INPUT
std::ifstream big_file("/tmp/hugeFile");
constexpr size_t ReadBufferSize = 1024;
char buffer[ReadBufferSize];
while (big_file) {
big_file.read(buffer, ReadBufferSize);
output_stream.write(buffer, big_file.gcount());
}
output_stream.close();
} catch (const Poco::Exception& ex) {
std::cout << "Error : (error code " << ex.code() << " (" << ex.displayText() << ")";
return EINVAL;
}
return 0;
}